I have hallway lights controlled by three separate switches; two 3-Pole and one 4-pole. One can turn on the lights with any switch and turn off the lights with any switch.

I have replaced one of the 3-pole switches with a 3-Pole occupancy sensor. My expectation was that the motion activation would substitute for manually flicking the switch and thereby turn on the light when motion was detected (and subsequently turn it off after timing out) while still allowing to turn on/off the same lights with either of the other two switches as needed. This has not turned out to be the case.

The 3-Pole box I tried these units in had one pair of black/white wires coming in and 2 blacks, a red and a white coming in (going out)on the other side. The white wires were connected with a twist on connector. From the examples in the instructions, this is a 3 way line or load set-up (although I cannot tell which).

Despite having played around with several combinations of wires to either sensor switch, the results seem to be about the same.

With power restored and the lights on, I can shut them off with the manual switch or let the timer shut them off. When I do this, neither of the other two switches will turn the lights back on. Alternatively, with the lights on, I can shut them off with either of the two straight switches and can turn them back on again with the same switch or the other simple switch. However, when I turn the lights off using either switch, the motion sensor switch does nothing. In fact it doesn't even appear to have power going to it unless I switch one of the other two back. The end result is I can either run the lights with the motion sensor switch and never touch the other two OR I use only the two mechanical switches and never use the motion sensor – either way defeats the purpose.

Aside from not being able to reason out what is going on here, I am also confused by both installation pamphlets. Although neither one states you need to alter the wiring anywhere but the switch you are replacing, both show an illustration of the sensor switch AND the "3-way switch" side-by-side and accompanying wiring. This somewhat suggests to me that the remaining 3-pole switch originally in this set-up has to also be re-wired. I haven't yet tried this since the instructions do not take into account if you are installing the sensor switch into a 2-switch system (3-pole) or one with 3 wall switches, one of which using a 4-pole switch and the other 2 3-pole.

What am I doing wrong?

Thank you for all the prompts responses. To clarify some of your comments/questions…

• Despite trying to figure this out myself, I don't understand the difference between "3-way" and "3-Pole". What's more, isn't confusing that if you was to have three switches working one light, you need a 4-Pole. The switch I bought said 3-Pole on it and it has an occupancy sensor and rocker switch (2-way?). The occupancy sensor has programmable sensitivity and time-out settings. Basically, it senses movement, turns the lights on then, after a set time, turns them off. There are 3 switches in the circuit but this is the only one with a sensor. It replaces an existing 3-pole switch (a simple rocker switch with three terminals and a ground). The other 2 switches are another 3-pole and a pole.

• These are links to the installations pamphlets:
  https://www.leviton.com/en/docs/IPS06_IPV06_Instruction_Sheet.pdf
  http://www.lutron.com/TechnicalDocumentLibrary/0301647.pdf
  I bought two different ones since the sensitivity on the first one didn't seem to trip when movement was off to the sides. I was surprised how different they were in construction and operation even though the description of their functionality on the package was nearly identical.

• I mentioned that prior to installing, the hallway light could be turned on/off by any of the three switches in any order and that I expected when I replaced the original switch with a motion sensor, that nothing would change except I wouldn't actually have to hit a switch to turn on the lights. What I failed to consider is that if it actually worked like that, that is, the switch is tripped everytime it sensed movement, it would turn on AND off constantly. Obviously, the sensor only turns the lights ON and the built in timer shuts it off.
  What it DOES NOT do and I hope to rectify is have the sensor turn on the lights as normal BUT if I want to manually turn them off before the timer does, I can, while still having the sensor turn it back on later. Currently, if I use one of the other two switches, it seems to isolate the sensor switch as it behaves as if it has no power. I've tried alternating the traveler wires and there is no different in functionality.